Long-Term Trends of Water Quality and Biotic Metrics in Chesapeake Bay: 1986 to 2008
We analyzed trends in a 23-year period of water quality and biotic data for Chesapeake Bay. Indicators were used to detect trends of improving and worsening environmental health in 15 regions and 70 segments of the bay and to assess the estuarine ecosystem’s responses to reduced nutrient loading from point (i.e., sewage treatment facilities) and non-point (e.g., agricultural and urban land use) sources. Despite extensive restoration efforts, ecological health-related water quality (chlorophyll-a, dissolved oxygen, Secchi depth) and biotic (phytoplankton and benthic indices) metrics evaluated herein have generally shown little improvement (submerged aquatic vegetation was an exception), and water clarity and chlorophyll-a have considerably worsened since 1986. Nutrient and sediment inputs from higher-than-average annual flows after 1992 combined with those from highly developed Coastal Plain areas and compromised ecosystem resiliency are important factors responsible for worsening chlorophyll-a and Secchi depth trends in mesohaline and polyhaline zones from 1986 to 2008.
KeywordsBiotic Chesapeake Bay Eutrophication Health indices Water quality
- Alden, III., R.W., D.M. Dauer, J.A. Ranasinghe, L.C. Scott, and R.J. Llansó. 2002. Statistical verification of the Chesapeake Bay Benthic Index of Biotic Integrity. Environmetrics 13: 473–498.Google Scholar
- Boynton, W.R., and W.M. Kemp. 2000. Influence of river flow and nutrient loads on selected ecosystem processes: A synthesis of Chesapeake Bay data. In Estuarine science, a synthetic approach to research and practice, ed. J.E. Hobbie, 269–298. Washington, D.C.: Island.Google Scholar
- Bricker, S., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, and J. Woerner. 2007. Effects of nutrient enrichment in the nation’s estuaries: A decade of change. NOAA Coastal Ocean Program decision analysis series no. 26, 328. Silver Spring: National Centers for Coastal Ocean Science.Google Scholar
- CBP Chesapeake Bay Monitoring Program Database. 2008. US environmental protection agency, Chesapeake Bay program office. http://www.chesapeakebay.net/. Accessed 20 March 2009.
- Filoso, S., and M. Palmer. 2010. Assessing stream restoration effectiveness at reducing nitrogen loads to downstream waters. Ecological Applications (in press).Google Scholar
- Keller, T.A., G.W. Shenk, M.R. Williams, and R.A. Batiuk. 2010. Development of a new indicator of pollutant loads and its application to the Chesapeake Bay watershed. River Research and Applications (in press).Google Scholar
- Kemp, W.M., W.R. Boynton, J.E. Adolf, D.F. Boesch, W.C. Boicourt, G. Brush, J.C. Cornwell, T.R. Fisher, P.M. Glibert, J.D. Hagy, L.W. Harding, E.D. Houde, D.G. Kimmel, W.D. Miller, R.I.E. Newell, M.R. Roman, E.M. Smith, and J.C. Stevenson. 2005. Eutrophication of Chesapeake Bay: Historical trends and ecological interactions. Marine Ecology Progress Series 303: 1–29. doi:10.3354/meps303001.CrossRefGoogle Scholar
- Lacouture, R.V., J.M. Johnson, C. Buchanan, and H.G. Marshall. 2006. Phytoplankton index of biotic integrity for Chesapeake Bay and its tidal tributaries. Estuaries and Coasts 29: 598–616.Google Scholar
- Langland, M.J., J.P. Raffensperger, D.L. Moyer, J.M. Landwehr, and G.E. Schwarz. 2006. Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985–2004: U.S. Geological Survey scientific investigations report 2006–5178, 75 pp.Google Scholar
- Lewis Jr., R.R., P.A. Clark, W.K. Fehring, H.S. Greening, R.O. Johansson, and R.T. Paul. 1998. The rehabilitation of the Tampa Bay Estuary, Florida, USA, as an example of successful integrated coastal management. Marine Pollution Bulletin 37: 468–473. doi:10.1016/S0025-326X(99)00139-3.CrossRefGoogle Scholar
- Llansó, R.J., F.S. Kelly, and L.S. Scott. 2005. Chesapeake Bay water quality monitoring program long-term benthic monitoring and assessment component level 1 comprehensive report. July 1984–December 2004 (Volume 1). Prepared for the MD Department of Natural Resources Assessment Services by Versar.Google Scholar
- McConnell, L.L., G.W. McCarty, T.R. Fisher, C.J. Hapeman, W.D. Hively, T.E. Jordan, M.W. Lang, C.P. Rice, A.M. Sadeghi, and D. Whitall. 2009. Choptank River conservation effects assessment project, 2004–2008. NRCS special emphasis watershed, final report. 15 p.Google Scholar
- NADP National Atmospheric Monitoring Database. 2008. National atmospheric deposition program. http://nadp.sws.uiuc.edu/sites/siteinfo.asp?net=NTN&id=MD13. Accessed 17 October 2008.
- Orth, R.J., D.J. Wilcox, L.S. Nagey, A.L. Owens, J.R. Whiting, and A.K. Kenne. 2005. 2004 Distribution of submerged aquatic vegetation in the Chesapeake Bay and Coastal Bays. VIMS special scientific report number 146. Final report to U.S. EPA, Chesapeake Bay Program, Annapolis, MD. Grant No. CB973013-01-0Google Scholar
- Orth, R.J., M.R. Williams, S.R. Marion, D.J. Wilcox, T.J.B. Carruthers, K.A. Moore, W.M. Kemp, W.C. Dennison, N. Rybicki, P. Bergstrom and R.A. Batiuk. 2010. Long-term trends in submersed aquatic vegetation (SAV) in Chesapeake Bay, USA, related to water quality. Estuaries and Coasts 33: 1144–1163. doi: 10.1007/s12237-010-9311-4.Google Scholar
- Testa, J.M. 2006. Factors regulating variability in water quality and net biogeochemical fluxes in the Patuxent River estuary. M.S. thesis, University of Maryland at College Park, College Park, MarylandGoogle Scholar
- Testa, J.M., W.M. Kemp, W.R. Boynton and J.D. Hagy III. 2008. Long-term changes in water quality and productivity in the Patuxent River estuary: 1985 to 2003. Estuaries and Coasts 31: 1021–1037. doi:10.1007/s12237-008-9095-y.
- U. S. Environmental Protection Agency. 2003. Ambient water quality criteria for dissolved oxygen, water clarity and chlorophyll a for Chesapeake Bay and tidal tributaries. U. S. Environmental Protection Agency 903-R-03-002. Washington, D.C.: Office of Water.Google Scholar
- U. S. Environmental Protection Agency. 2004. Chesapeake Bay program analytical segmentation scheme. Revisions, Decision, and Rationales 1983–2003. 64p. www.chesapeakebay.net/content/publications/cbp_13272.pdf.
- U.S. Geological Survey Surface Water Data. 2008. River Input Monitoring Program. va.water.usgs.gov/chesbay/RIMP/index.html. Accessed 3 December 2008.Google Scholar